[PATCH 1/2] drm/xe/guc: Fix out-of-bound while enabling engine activity stats

[Michal Wajdeczko]

In the PF mode we allocate array of struct engine_activity_group
that holds activity data split for the PF and all potential VFs.
But while preparing data for use by VFs we ended with bad index.

 [ ] BUG: KASAN: slab-out-of-bounds in xe_guc_engine_activity_function_stats+0x41e/0x4f0 [xe]
 [ ] Call Trace:
 [ ]  <TASK>
 [ ]  dump_stack_lvl+0x91/0xf0
 [ ]  print_report+0xd1/0x680
 [ ]  ? __virt_addr_valid+0x23a/0x440
 [ ]  ? kasan_addr_to_slab+0xd/0xb0
 [ ]  kasan_report+0xe7/0x130
 [ ]  ? xe_guc_engine_activity_function_stats+0x41e/0x4f0 [xe]
 [ ]  ? xe_guc_engine_activity_function_stats+0x41e/0x4f0 [xe]
 [ ]  __asan_report_store8_noabort+0x17/0x30
 [ ]  xe_guc_engine_activity_function_stats+0x41e/0x4f0 [xe]
 [ ]  pf_engine_activity_stats+0x1b6/0x7f0 [xe]
 [ ]  ? kobject_put+0x5f/0x470
 [ ]  xe_pci_sriov_configure+0x28c9/0x3270 [xe]
 [ ]  ? __pfx_dev_attr_store+0x10/0x10
 [ ]  ? kstrtoull+0x3b/0x70
 [ ]  ? __pfx___lock_acquire+0x10/0x10
 [ ]  ? kstrtou16+0x65/0xf0
 [ ]  sriov_numvfs_store+0x20c/0x400
 [ ]  ? __pfx_sriov_numvfs_store+0x10/0x10
 [ ]  ? __pfx__copy_from_iter+0x10/0x10
 [ ]  ? __pfx_dev_attr_store+0x10/0x10
 [ ]  dev_attr_store+0x3b/0x80
 [ ]  ? sysfs_file_ops+0x135/0x190

Fixes: 2de3f38fbf89 ("drm/xe: Add support for per-function engine activity")
Signed-off-by: Michal Wajdeczko <michal.wajdeczko at intel.com>
Cc: Umesh Nerlige Ramappa <umesh.nerlige.ramappa at intel.com>
Cc: Riana Tauro <riana.tauro at intel.com>
---
 drivers/gpu/drm/xe/xe_guc_engine_activity.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_guc_engine_activity.c b/drivers/gpu/drm/xe/xe_guc_engine_activity.c
index b96fea78df8b..0fb48f8f05d8 100644
--- a/drivers/gpu/drm/xe/xe_guc_engine_activity.c
+++ b/drivers/gpu/drm/xe/xe_guc_engine_activity.c
@@ -304,6 +304,8 @@ static void engine_activity_set_cpu_ts(struct xe_guc *guc, unsigned int index)
 	struct engine_activity_group *eag = &engine_activity->eag[index];
 	int i, j;
 
+	xe_gt_assert(guc_to_gt(guc), index < engine_activity->num_activity_group);
+
 	for (i = 0; i < GUC_MAX_ENGINE_CLASSES; i++)
 		for (j = 0; j < GUC_MAX_INSTANCES_PER_CLASS; j++)
 			eag->engine[i][j].last_cpu_ts = ktime_get();
@@ -374,8 +376,9 @@ static int engine_activity_enable_function_stats(struct xe_guc *guc, int num_vfs
 		return ret;
 	}
 
-	for (i = 0; i < engine_activity->num_functions; i++)
-		engine_activity_set_cpu_ts(guc, i + 1);
+	/* skip PF as it was already setup */
+	for (i = 1; i < engine_activity->num_functions; i++)
+		engine_activity_set_cpu_ts(guc, i);
 
 	return 0;
 }
-- 
2.47.1